So far we’ve managed to create our first ROM, with just one instruction that sets the register d0. The next thing I would like to do is draw something on the screen, but before that we need some more info on how this old console produced those awesome graphics we all know and love.

Introduction

I started looking into Mega Drive development in early September 2015. My excuse for doing so was that I was going to take a class the same year, about microprocessors, in which we were going to learn 68K assembly, so I would check my code on a real system. It turns out we didn’t, but the excuse did its job and I’ve had great fun with this project since.